US Patent 7889992 Hybrid superconductor-optical quantum repeater

A hybrid superconductor-optical quantum repeater is provided. The hybrid superconductor-optical quantum repeater comprises an optical subsystem configured to receive an optical signal via an optical channel and a superconductor subsystem coupled to the optical subsystem. The optical subsystem and superconductor subsystem are coupled to one another via a microwave transmission medium. The optical subsystem is configured to receive an optical signal via the optical channel and down-convert a photon of the optical signal to a microwave photon in a microwave output signal that is output to the superconductor subsystem via the microwave transmission medium. The superconductor subsystem stores a quantum state of the microwave photon and transmits the microwave photon along an output channel from the superconductor subsystem.